1 /* $Id$ */

     2 

     3 /** @file zoom_func.hpp */

     4 

     5 #ifndef ZOOM_FUNC_H

     6 #define ZOOM_FUNC_H

     7 

     8 #include "zoom_type.h"

     9 

    10 extern ZoomLevel _saved_scrollpos_zoom;

    11 

    12 /**

    13  * Scale by zoom level, usually shift left (when zoom > ZOOM_LVL_NORMAL)

    14  * When shifting right, value is rounded up

    15  * @param value value to shift

    16  * @param zoom  zoom level to shift to

    17  * @return shifted value

    18  */

    19 static inline int ScaleByZoom(int value, ZoomLevel zoom)

    20 {

    21 	if (zoom == ZOOM_LVL_NORMAL) return value;

    22 	int izoom = zoom - ZOOM_LVL_NORMAL;

    23 	return (zoom > ZOOM_LVL_NORMAL) ? value << izoom : (value + (1 << -izoom) - 1) >> -izoom;

    24 }

    25 

    26 /**

    27  * Scale by zoom level, usually shift right (when zoom > ZOOM_LVL_NORMAL)

    28  * When shifting right, value is rounded up

    29  * @param value value to shift

    30  * @param zoom  zoom level to shift to

    31  * @return shifted value

    32  */

    33 static inline int UnScaleByZoom(int value, ZoomLevel zoom)

    34 {

    35 	if (zoom == ZOOM_LVL_NORMAL) return value;

    36 	int izoom = zoom - ZOOM_LVL_NORMAL;

    37 	return (zoom > ZOOM_LVL_NORMAL) ? (value + (1 << izoom) - 1) >> izoom : value << -izoom;

    38 }

    39 

    40 /**

    41  * Scale by zoom level, usually shift left (when zoom > ZOOM_LVL_NORMAL)

    42  * @param value value to shift

    43  * @param zoom  zoom level to shift to

    44  * @return shifted value

    45  */

    46 static inline int ScaleByZoomLower(int value, ZoomLevel zoom)

    47 {

    48 	if (zoom == ZOOM_LVL_NORMAL) return value;

    49 	int izoom = zoom - ZOOM_LVL_NORMAL;

    50 	return (zoom > ZOOM_LVL_NORMAL) ? value << izoom : value >> -izoom;

    51 }

    52 

    53 /**

    54  * Scale by zoom level, usually shift right (when zoom > ZOOM_LVL_NORMAL)

    55  * @param value value to shift

    56  * @param zoom  zoom level to shift to

    57  * @return shifted value

    58  */

    59 static inline int UnScaleByZoomLower(int value, ZoomLevel zoom)

    60 {

    61 	if (zoom == ZOOM_LVL_NORMAL) return value;

    62 	int izoom = zoom - ZOOM_LVL_NORMAL;

    63 	return (zoom > ZOOM_LVL_NORMAL) ? value >> izoom : value << -izoom;

    64 }

    65 

    66 #endif /* ZOOM_FUNC_H */